Battery Grounding

S

SAL568

Member
Location
Pakistan
Occupation
Engineer
Hey Mike
Should we ground battery negative/positive in a domestic solar system?
(battery terminals give shock).
 
PaulMmn

PaulMmn

Senior Member
Location
Union, KY, USA
Occupation
EIT - Engineer in Training, Lafayette College
"Give shock" when you touch both battery terminals (hopefully with the same hand)?
How much voltage? Even a 9-volt 'transistor battery' will make your tongue tingle.
.
Battery Test.jpeg
 
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
SAL568 said:
Hey Mike
Should we ground battery negative/positive in a domestic solar system?
(battery terminals give shock).
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The answer is probably 'No' nowadays, or that your battery will be grounded by other equipment. But we'd need a lot more detail about the system you are installing.
 
S

SAL568

Member
Location
Pakistan
Occupation
Engineer
jaggedben said:
The answer is probably 'No' nowadays, or that your battery will be grounded by other equipment. But we'd need a lot more detail about the system you are installing.
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Inverter is not grounded as there no ground/earthing conductor at all. The power lines coming from grid does not supply any ground either.
 
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
SAL568 said:
Inverter is not grounded as there no ground/earthing conductor at all. The power lines coming from grid does not supply any ground either.
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Is this an off-grid or grid tied solar system? What is the system voltage? How much power? What does the inverter manual say about grounding and ground fault detection? Do you have a charge controller? Are DC loads supplied or just the inverter?

Let's also not confuse actual earthing (i.e. installing and connecting electrodes) with system grounding (choice of whether to ground a circuit conductor and which one). Your inverter or other equipment may bond neutral to its PE terminal even if you don't connect a grounding electrode to the PE.

Reasons to bond and ground a battery conductor (usually negative) include providing a fault current path to open a fuse or circuit breaker in case of a ground fault. However if your inverter or charge controller already has ground-fault protective devices they may take care of that or not work correctly if you ground the battery solidly somewhere else.

SAL568 said:
It's located in Pakistan. Grid meaning utility power
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Are you trying to follow the NEC? Or another safety standard?

SAL568 said:
Usually there is no grounding or earthing or any other protection system employed. Just 2 wires L & N
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N is likely grounded somewhere on the utility network, but you should ask someone local. There are no RCDs?
 
Joe.B

Joe.B

Senior Member
Location
Myrtletown Ca
Occupation
Building Inspector
SAL568 said:
Seeing you as senior member here I didn't expect such response from you
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Being a "Senior Member" here only means you've made it past a certain number of posts without getting kicked out. 250 I think?

I've been in a few situations where cultural differences can make communication challenging. I think it can be even more amplified when dealing with text only communication. I don't think @PaulMmn meant any disrespect by his response.

One of my co-workers is not from the US and English is his third language. Generally we communicate very well, but I tend to have sarcastic responses that I mean to be lighthearted and funny. He finds those responses to be rude and disrespectful. I have learned to be more careful with my communication, and he has learned not to take things personally. It's all about balance.
 
S

SAL568

Member
Location
Pakistan
Occupation
Engineer
jaggedben said:
Is this an off-grid or grid tied solar system? What is the system voltage? How much power? What does the inverter manual say about grounding and ground fault detection? Do you have a charge controller? Are DC loads supplied or just the inverter?

Let's also not confuse actual earthing (i.e. installing and connecting electrodes) with system grounding (choice of whether to ground a circuit conductor and which one). Your inverter or other equipment may bond neutral to its PE terminal even if you don't connect a grounding electrode to the PE.

Reasons to bond and ground a battery conductor (usually negative) include providing a fault current path to open a fuse or circuit breaker in case of a ground fault. However if your inverter or charge controller already has ground-fault protective devices they may take care of that or not work correctly if you ground the battery solidly somewhere else.


Are you trying to follow the NEC? Or another safety standard?


N is likely grounded somewhere on the utility network, but you should ask someone local. There are no RCDs
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1) It's a 6kw off-grid solar system. Growatt ( Spf6000) inverter is used.Manual says(GROUNDING INSTRUCTIONS -This inverter should be connected to a permanent grounded wiring system. Be sure to comply with local requirements and regulation to install this inverter. ). It's 230v system single phase.

2) My scope is to connect the Inverter to grounding following NEC.

3) No RCDs installed

Here people dont follow any standard or code so no help from locals.
 
tortuga

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
SAL568 said:
2) My scope is to connect the Inverter to grounding following NEC.
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Even if they don't follow the standard you need find it out.
To know what kind of earthing system your utility is using is very important.
And it cant be that hard to know what electrical code covers your installation before you connect to it.

If you impose the NEC on a IT earthing system you could make it less safe or cause problems.
I *think* Pakistan still uses the British Standards such as BS 7671, BS 7340 and the IEC 60364 for earthing.

North America LV utility distribution is a TN-C-S (PME) system or what we call Multi grounded neutral MGN.
My guess is where you are is either a what we call a resistance grounded or IT system or a TN-C-S PNB (protective neutral bonding) system which is they type of system we run on the customer side where ground a neutral are combined at only one point then separate.
Hope this helps
 
PaulMmn

PaulMmn

Senior Member
Location
Union, KY, USA
Occupation
EIT - Engineer in Training, Lafayette College
I thank Joe B for his comments-- and I agree, I intended no disrespect. I feel that what I think is a humorous response is sometimes needed, although my sense of humour sometimes veers in strange directions.
 
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I'm aware Growatt sells inverters in the US but I haven't used them. I assume they have NEC compliant ground fault detection. I don't know if their 230V inverters that they sell internationally would also have the same ground fault detection. If they don't, then you can't really make the installation NEC compliant in that respect.

Regardless, I would read the inverter manual carefully and not bond any conductor except if they very clearly instruct you to. On a non-isolated inverter you could possibly cause a dead short and kill the inverter by doing that.

I presume the grounding instruction you quoted means to connect a grounding electrode to a PE terminal on the inverter.
 
rambojoe

rambojoe

Senior Member
Location
phoenix az
Occupation
Wireman
PaulMmn said:
I thank Joe B for his comments-- and I agree, I intended no disrespect. I feel that what I think is a humorous response is sometimes needed, although my sense of humour sometimes veers in strange directions.
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No one likes my helen keller jokes- if that helps...
 
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